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From: Lukas Wunner <lukas@wunner.de>
To: Damir Chanyshev <conflict342@gmail.com>
Cc: "Bjorn Helgaas" <helgaas@kernel.org>,
	linux-pci@vger.kernel.org,
	"Logan Gunthorpe" <logang@deltatee.com>,
	"Michael J. Ruhl" <michael.j.ruhl@intel.com>,
	"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Subject: Re: P2PDMA support status for the sappire rapids+
Date: Tue, 8 Apr 2025 17:28:56 +0200	[thread overview]
Message-ID: <Z_VAuOu7lvm5ykNX@wunner.de> (raw)
In-Reply-To: <CAAUwoOg-uUGRcyNx3npvJuA9ZQa=dH+7tzdtKnA1y69kBriyuw@mail.gmail.com>

On Tue, Apr 08, 2025 at 06:14:55PM +0300, Damir Chanyshev wrote:
> On Tue, Apr 8, 2025 at 6:06???PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > The pci_p2pdma_whitelist[] is only updated when somebody tests a
> > platform and determines that its RC can route peer-to-peer
> > transactions between separate Root Ports.  This routing is not
> > required by the PCIe spec, so we can't assume that all platforms
> > support it.
> 
> For the testing, is simple rdma ping-pong sufficient? Or a more
> specific testing tool?
> Unfortunately I don't have a fancy pcie hardware analyzer.

You should test that performance is satisfactory for you needs.

There are claims that older Intel CPUs have poor p2pdma performance:
https://lore.kernel.org/all/e2c56983-0111-4132-ae17-0095aa33fd2d@deltatee.com/

Thanks,

Lukas

  reply	other threads:[~2025-04-08 15:28 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-08 14:48 P2PDMA support status for the sappire rapids+ Damir Chanyshev
2025-04-08 15:06 ` Bjorn Helgaas
2025-04-08 15:14   ` Damir Chanyshev
2025-04-08 15:28     ` Lukas Wunner [this message]
2025-04-08 16:25       ` Logan Gunthorpe
2025-04-08 15:11 ` Lukas Wunner

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